Induction of apoptosis by Polygonatum odoratum lectin and its molecular mechanisms in murine fibrosarcoma L929 cells

Background: The Galanthus nivalis agglutinin (GNA)-related lectins have been reported to bear antiproliferative and apoptosis-inducing activities in cancer cells; however, the precise mechanisms by which GNA-related lectins induce cell death are still only rudimentarily understood. Methods: In the present study, Polygonatum odoratum lectin (designated POL), a mannose-binding specific GNA-related lectin, possessed a remarkable antiproliferative activity toward murine fibrosarcoma L929 cells. And, this lectin induced L929 cell apoptosis in a caspase-dependent manner. In addition, POL treatment increased the levels of FasL and Fas-Associated protein with Death Domain (FADD) proteins and resulted in caspase-8 activation. Also, POL treatment caused mitochondrial transmembrane potential collapse and cytochrome c release, leading to activations of caspase-9 and caspase-3. Moreover, POL treatment enhanced tumor necrosis factor alpha (TNF alpha)-induced L929 cell apoptosis. Results: Our data demonstrate for the first time that this lectin induces apoptosis through both death-receptor and mitochondrial pathways, as well as amplifies TNF alpha-induced L929 cell apoptosis. General significance: These inspiring findings would provide new molecular basis for further understanding cell death mechanisms of the Galanthus nivalis agglutinin (GNA)-related lectins in future cancer investigations. (C) 2009 Elsevier B.V. All rights reserved.